Strand monitoring method and device



July 23, 1968 P. POREBSKI ET AL 3,394,206

STRAND MONITORING METHOD AND DEVICE 5 Sheets-Sheet 1 Filed Feb. 28, 1964 INV NTO LEOPOLD P. EORE?SKI JAMES A. LIGHT AGENT July 23, 1968 L. P. POREBSKI ET AL 3,394,206

STRAND MONITORING METHOD AND DEVICE Filed Feb. 28, 1964 5 Sheets-Sheet 2 FIG. 4

FIG. 5

INVENTORS LEOPOLD P. POREBSKI J'AMES A. LIGHT July 23, 1968 P RE ET AL 3,394,206

STRAND MONITORING METHOD AND DEVICE 5 Sheets-Sheet 5 Filed Feb. 28, 1964 FIG.

INVENTORS LEOPOLD F? POREBSKI J'AMES A. LIGHT AGENT United States Patent f 3,394,206 STRAND MONITORING METHOD AND DEVICE Leopold P. Porebski, Richmond, and James A. Light,

Prince George, Va., assignors to Allied Chemical Corporation, New York, N.Y., a corporation of New York Filed Feb. 28, 1964, Ser. No. 348,036

Claims. (Cl. 264-40) ABSTRACT OF THE DISCLOSURE An apparatus for monitoring the quality of a running strand which detects positive variations in strand diameter and separates the defective portion of the strand. A slotted, pivotally mounted strand thickness gauge responds to an increase in the strand diameter and in so doing actuates a deflector which deflects the running strand out of its normal pathway and into contact with a strand severing means.

This invention relates to a device for the continuous monitoring of a running strand, e.g. a yarn, and for segregating otf quality yarn. The device of the invention is particularly useful in monitoring the yarn from melt spinning operations.

In the melt spinning of continuous filaments such as in the case of the spinning of yarn from synthetic polymers, generally the molten polymer is extruded through a plurality of orifices which is commonly called the spinnerette, drawn into continuous filaments and wound up on reels. Prior to its extrusion, the melt is filtered to remove therefrom solid occlusions, such as carbonaceous particles, as well as gaseous occlusions in the form of bubbles and the like; but some such occlusions may escape the filter. Such occlusions eventually lead to a partial blocking of the extrusion orifices. The extrusion orifices also may become partially blocked when decomposition of the molten polymer forms carbonaceous matter at the exit from the orifice.

When an orifice is partially blocked, the molten polymer flows less rapidly therein; and when carbonaceous matter accumulates at the exit, the issuing molten polymer tends to cling there, especially if it is flowing relatively slowly. The accumulated polymer decomposes, aggravating the problem. Eventually a drop is formed which is carried down with the filament and forms a point of enlargement thereon, often entangling other filaments and cementing them together. Such enlarged points, known as slubs, show up as quality defects in the yarn since they adversely affect drawability, cause non-uniform dyeing, etc.

In melt spinning operations there is generally an entire bank or a number of banks of spinning positions employed, where bundles of synthetic filaments are spun at several dozens of positions simultaneously. Since visual observation of even a single bundle of filaments for quality defects such as slubs is in itself an impossible task at normal spinning speeds, the problems of quality monitoring of the bundles obtained by melt spinning presents a need for an accurate, simple and inexpensive monitoring device. A further desirable feature of such device is that it act to segregate off-quality yarn as soon as it has been detected; and a still further desirable feature is that the device set off a signal when off-quality yarn is detected. A device of the type desired should, upon the sensing the defect and severance of the strand, continue the takeup of the extruded yarn, so as to maintain the spinning equilibrium.

The apparatus of the present invention possesses the desirable features enumerated above.

While the device of the invention is to be described "ice mainly in relation to the melt spinning of synthetic polymer filaments, it is to be understood that the device is equally applicable for the continuous monitoring of a large variety of other types of running strands, such as continuously running yarns being drawn, wound, or otherwise processed or treated.

The features of the present invention will be more fully understood from the following description and the accompanying drawings, wherein:

FIG. 1 is a schematic showing of a melt spinning operation;

FIG. 2 is a perspective of an embodiment of the device of the invention;

FIG. 3 is a cross sectional view taken along line 3-3 of FIG. 2;

FIG. 4 is a front elevational view of the device of FIG. 2 in the tripped position;

FIG. 5. is a back elevational view of the device of FIG. 2; and

FIG. 6 is a perspective of another embodiment of the invention.

In its broader aspects the apparatus of the invention includes a gauge which senses variations above a predetermined minimum in a yarn property, e.g. enlargement of the diameter of the yarn; and upon sensing such a change, the gauge actuates a deflector which pushes the yarn out of its normal path. The yarn, as soon as it is pushed out of its normal path, engages severing means which serve to segregate the off-quality yarn.

In FIG. 1 the schematic layout of a typical melt spinning operation is shown. Particles of polymer material are stored in a hopper 100, from where the particulate polymer is metered into a melter 102. The material is subjected to heat and melted here, and is driven under pressure generated by a pump 104 through a sand pack 106 to a spinnerette 108, which comprises a plate with a number of orifices therein through which the molten polymer is extruded. The molten polymer jetting out through these orifices travels downward through quench stack 110' so as to solidify the individual filaments, forming a yarn bundle. The monitoring device 112 of the invention can advantageously be disposed at a point where the filaments leave the quench stack 110. The yarn can then be brought in contact with a finish applicator 114 which applies a surface lubricant to the fiber. Then the yarn passes about a lower Godet roll 116 and an upper Godet roll 118 and then is taken up on a wind-up roll 120.

In FIG. 2 an embodiment of the monitoring device of the invention is shown. Mounting plate 2, with the device of the invention mounted thereon, is disposed below the quench stack 110 to receive the yarn issuing therefrom in a downward direction. A bearing support 4 is firmly attached to the mounting plate 2. A hearing (not shown) is mounted on the plate 2 by means of the bearing support 4. One end of a shaft 6 is mounted for rotation in the bearing within the bearing support 4.

A gauge 8 is mounted on the shaft 6 and is adapted to rotate the shaft by downward movement. The gauge consists of a plate 10, one end of which is free and the other end attached to the shaft 6 by means of screws 12. An elongated U-shaped slot 14 is provided in the plate 10, the slot being open toward the free end of plate 10. As also shown in FIG. 3, the plate 10 is provided with sidewalls 15, and a pair of gauge bars 16, made of an abrasion resistant ceramic or metal, such as porcelain, glass, aluminum-silicon-magnesium alloy, etc., are disposed within the sidewalls. A slot 14a is provided between the gauge bars 16, which is set to correspond to the predetermined maximum filament diameter intended to pass through the gauge 8 without being detected thereby. After the slot 14a has been adjusted by shims or the like, the gauge bars 16 are cemented to the gauge plate 10.

The open ends of the slots 14 and 14a are partially enclosed by a crescent-shaped knife blade 18 which is secured at one end thereof to one of the free ends of the gauge plate by a screw 20. A clearance is provided between the free end of the knife blade 18 and the end of plate 10 to provide access to the slot 14a when a strand of yarn is to be introduced thereinto. Moreover the entrance to slot 14a is set back from the knife blade and is enlarged to facilitate entrance of the yarn.

A pair of trunnions 22 are provided in opposite outer sides of the plate 10 adjacent the shaft 6. A pair of bushings 24, each rotatably mounted on a trunnion 22, carry rods 26 which support deflector 28. Deflector 28 has a concave surface made of rubber, cork or other like material with high coeflicient of friction. A support bracket 30, welded to the supporting rods 26 is provided to limit the counterclockwise rotation of the rods 26 to a point only slightly off vertical when the gauge 8 is in its normal horizontal position.

A rod 32 extends oppositely to plate 10 through a bore in rotatable shaft 6. A set screw 33 is provided for an adjustably fixed disposition of the rod 32 in the shaft 6. A counterweight 34 is attached near the end of rod 32, opposite to guage 8. The counterweight 34, in the normal horizontal position of the gauge 8 tends to rotate the shaft 6 against a limiting pin 36 attached to the bearing support 4, thus holding the gauge 8 substantially horizontal against a torque which is adjustable by varying the length of the lever arm provided by counterweight 34 and its distance from the shaft 6.

As shown in FIG. 5, a back-up ring 38 for the bearing support 4 is attached by socket screws 40 to the back side of the mounting plate 2. As can be seen, the shaft 6 is hollow. One leg of a rectangular mercury switch 42 is disposed within the hollow of the shaft for rotation with the shaft. The switch is disposed so that it is open when the gauge 8 is in the horizontal position, and the mercury within the switch 42 establishes electrical contact between two poles 43 when the shaft 6 is rotated by downward motion of gauge 8.

In operation, the above-described embodiment of the device of the invention is adapted to sever a running strand by snubbing it around the cutting knife edge. Thus as long as the yarn Y travels through the gauge 8 in the direction of the arrow of FIG. 1, the gauge is disposed horizontally, as shown in FIG. 2. When an enlarged diameter portion of one or more of the passing yarns reaches the gauge 8, which diameter is larger than the width of the slot 14a, the further passage of the yarn through the gauge is blocked; but since the lower Godet roll 116, the upper Godet roll 118, and the wind-up roll 120 of FIG. 1 continue to pull the yarn, the gauge 8 will start to pivot in the clockwise direction about the shaft 6 (FIG. 2), against the torque of the counterweight 34, until the monitoring gauge and plate 10 reach alignment with the advancing strand as shown in FIG. 4. During this movement the mercury in the switch 42 establishes contact between the two poles of the switch which results in the actuation of suitable alarms, such as indicator lamps, buzzers, etc.

As plate 10 moves toward the vertical position of FIG. 4, the yarn deflector is carried against the yarn and pivots downward, about the trunnions 22. The deflector 28 bears against the yarn, snubbing it and carrying it firmly and without slipping against knife edge 18 which then becomes a second snubbing point, as seen in FIG. 4. As the yarn is then pulled downward by the Godet rolls it is pulled against the knife edge 18, and is thus severed.

In an alternative embodiment (not shown), the knife edge is disposed at the location shown for surface 28 and merely a rounded rather than sharp snubbing point is provided at the open end of the slots 14 and 14a. The yarn is then carried upwards, after deflector 28 has been tripped as against the knife at 28 and is thereby severed.

The deflector 28 besides serving to snub the yarn for severance, also serves to deflect the yarn from its normally vertical path to wind upon the upper Godet roll 118 when, as preferred, this roll is disposed slightly above the deflector and through the plane of rotation of the deflector. The advancing length of yarn, after severance, is then directed by the deflector into contact with the upper Godet roll. The Godet roll has a polished metal surface which manifests the known tendency to pick up the yarn, hence the yarn winds up onto the roll. By thus maintaining continuous take-up of the extruded yarn, interruption of extrusion and the irregularities consequent on restarting the extrusion are avoided; and spinning of quality yarn can be immediately resumed when the defect which caused the monitor to operate has been remedied. At the same time it is assured that no defective yarn is wound onto the windup roll 120.

The operator who is put on notice by the alarm actuated by the switch 42, can examine the spinnerette and eliminate the particular condition which caused the diameter enlargement in the filaments, and then simply restart the normal operation by threading the yarn into the slot of gauge 8 and about the Godet rolls. The waste fiber which was wound in the meantime on the upper Godet roll is discarded.

The knife edge 8 is advantageously crescent-shaped so as to catch and gather in its concave edge all, yarns to be severed, and at the same time the convex outer, blunt edge, aids in the quick rethreading of the monitoring device.

In FIG. 6 another embodiment of the invention is shown, wherein the monitoring apparatus does not require a cutter to effect severance of defective yarn. A bearing (not shown) is attached to a mounting plate 52 by a bearing support 54 to rotatably attach a shaft 56 to the mounting plate. A gauge 58 comprises a plate 60, attached by screws 62 to the shaft 56 for rotation therewith. The plate 60 is provided with a U-shaped slot 64 which is rimmed by a pair of parallel gauge bars 66, defining a slot 64a therebetween. The structure of the de vice described up to this point is identical with that shown in FIGS. 2-4.

A fixed end of a spring 68, which can be a strip or leaf of spring steel, a coil spring or the like, is held tight in a vise 70 which is mounted on the mounting plate 52. The other end of the spring is normally held back under tension. It carries a deflector arm 72 which protrudes outwardly and forwardly with reference to the spring to engage the yarn bundle when the spring is released. A hooked latch member 74 is rotatably mounted on the plate 52 at 76. The spring 68 is shown in its normal cocked position with the end carrying the deflector arm 72 being held back under tension by the hooked portion of the latch member 74. The shaft 56 is formed with an enlarged base 78 in which a latch releasing pin 80 is radially set.

A rod 82 extends through a bore in the shaft 56, oppositely to plate 60, rod 82 having at its one end a counterweight 84. The other end of the rod 82 is adapted to abut against a limiting pin 86 protruding from the bearing support 54. The position of the rod 82, and the lever age exercised by the counterweight 84 can be adjusted with the aid of a set-screw 83 adjustably fixing the distance of the counterweight 84 from the shaft 56. This counterweight arrangement of the presently described embodiment of the invention is identical to the arrangement of the embodiment of the invention shown in FIGS. 2-4.

As a yarn moves between the gauge bars 66, any section of enlarged diameter encounter the parallel gauge bars 66 and rotates the gauge in the traveling direction of the yarn in the same manner for the embodiment first described. The shaft 56 of the device is thereby rotated in the clockwise direction, bringing the latch releasing pin 80 against the lower end of the latch member 74 and slightly rotating the latch about the pivot 76 in the counterclockwise direction. Thereupon the hook on the top of the latch member releases the end of the spring 63 carrying deflector 72. The deflector '72 is carried against the yarn by the whipping action of the spring 68, whereby the yarn is pushed out from the slot 64a between the parallel gauge bars 66, and is Whipped against the upper Godet roll 118 (FIG. 1). The segment of the yarn contacting upper roll 11% proceeds to wind about the upper Godet roll. Since the lower Godet roll 116 and the upper Godet roll 118 rotate in opposite directions, the yarn will be broken between them by the ensuing tension. The windup of the yarn extruded after the severance continues on the upper Godet roll 118 as when using the first described embodiment of this invention.

The embodiment of the invention illustrated in FIG. 6 is preferably also provided with an alarm-actuating switch, such as the one shown in FIG. 6.

We claim:

1. Process of detecting and segregating detects in yarn as it is being spun, without breaking the continuity of the spinning operation, which comprises passing said yarn first around a lower roll and then around an upper roll; detecting yarn defects at a location, with reference to the running direction of the strand, in advance of the lower roll; and in response to detection of a defect, deflecting a segment of said yarn, located above the defect, into contact with said upper roll before the segment has contacted the lower roll; and with the aid of opposing pulls set up after the deflection, severing the yarn at a point before it contacts the lower roll, whereby the yarn being melt spun is thereafter wound onto the upper roll and by-passes the lower roll.

2. An apparatus for monitoring the quality of a running strand and segregating off-quality production comprising: a slotted gauge responsive to an increase in the diameter of the strand; said slotted gauge being further characterized by maintaining constant slot width during the monitoring and segregating of off-quality production; a rotatable shaft adapted to rotate upon actuation by the gauge; a deflector activated by the rotation of the shaft for changing the path of the running strand, said deflector being carried by a spring, one end of said spring being fixed and the other end of said spring being releasably held under tension and carrying said deflector; a pivotable latch normally holding the releasable end of the spring under tension, said latch being adapted to release the releasable end of the spring upon pivoting; means on the rotatable shaft for pivoting the latch upon rotation of the shaft; and means for severing the strand upon deflection of the strand by the deflector.

3. The apparatus of claim 2, further including alarm means for signalling when said gauge responds to :a variation in the diameter of the yarn.

4. An apparatus for the monitoring of slubs in a running yarn, comprising at least a pair of parallel members defining a space therebetween normally accommodating the running yarn; a rotatable shaft; means for mounting said parallel members cantilevered from said rotatable shaft to actuate rotation of the shaft; a yarn deflector positioned, with reference to the running direction of the yarn, in advance of said pair of parallel members, said yarn deflector being adapted to be moved toward the running yarn when said shaft is rotated, whereby said deflector is brought to bear upon and snub the running yarn in advance of said pair of parallel members when said shaft is rotated; and a knife blade mounted at the opposite end of the pair of parallel members from the deflector and intersecting the plane of movement of the deflector.

5. The apparatus of claim 4, wherein said yarn deflector is pivotally mounted from said parallel members to follow the rotary movement thereof with the rotation of said rotatable shaft.

6. The apparatus of claim 5, wherein said knife blade is crescent shaped and has a cutting edge on the concave edge with the edge opposite the cutting edge being convex.

7. An apparatus for monitoring the quality of a running strand, comprising a counterbalanced member pivotally mounted for movement in the running direction of the strand, said counterbalanced member having a strand guide slot; adjustable counterbalancing means for said counterbalanced member; a yarn deflector pivotally supported, with reference to the running direction of the strand, in advance of said counterbalanced member; and a stationary cutting lade attached to said counterbalanced member terminally of the guide slot, whereby rotation of the yarn deflector carries the yarn against the said cutting blade.

8. In a melt spinning apparatus having an upper roll and a lower roll: A strand monitoring device disposed, with reference to the running direction to the strand, in advance of the lower roll and including a movably mounted strand guide; a strand deflector mounted adjacent and below the upper roll, said strand deflector being adapted to move against the strand upon movement of said strand guide and to thus deflect a segment of the strand into contact with the upper roll before that segment has contacted the lower roll, and to bring about severance of the strand at a point before it contacts the lower roll, whereby the strand being melt spun is wound onto the upper roll and by-passes the guide and lower roll.

9. In a melt spinning apparatus having an upper roll and a lower roll: A strand monitoring device disposed with reference to the running direction of the strand in advance of the lower roll, said strand monitoring device including a movably mounted strand guide, a strand deflector mounted adjacent and below the upper roll; a spring having one end fixed and the other end carrying said deflector, a latch normally holding said deflector stationary and said spring under tension, said latch being adapted to release said deflector upon movement of said guide, and said spring being mounted to carry said deflector against the running strand upon the release of said latch, whereby the strand is deflected into contact with the upper roll which thereupon in cooperation with the lower roll breaks the strand between the two rolls allowing the upper roll to take up the strand being melt spun which by-passing the guide and lower roll.

10. An apparatus for the monitoring of the quality of a running strand, comprising at least a pair of members spaced apart from each other to provide a spaced therebetween, said space being adapted to permit the passage therethrough of the strand when the diameter of said strand is less than about the width of said space, a rotatable shaft, means for mounting said members upon said rotatable shaft to actuate rotation of said shaft, and alarm means responsive to the rotation of said shaft for signaling when said shaft rotates.

References Cited UNITED STATES PATENTS 608,867 8/1898 Junghans et a1. 58-16 1,749,511 3/ 1930 Sands 28-64 1,158,610 11/1915 Whitman 11663 1,784,141 12/1930 Hastings 2864 1,897,518 2/1933 Humphrey 28-64 2,434,091 1/ 1948 Arrington 28 -64 2,623,265 12/ 1952 Abbott 28-64 2,732,610 1/1956 Perry 28-64 2,964,828 12/1960 Sharps 28-64 3,071,839 1/1963 Marshall 2864 JAMES A. SEIDLECK, Primary Examiner.

P. E. ANDERSON, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,394,206 v July 23, 1968 Leopold P. Porebski et a1.

It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 5, line 18, "detects" should r ead defects line 55, "accommodating" should read accommodating Column 6, line 18, "to" should read of line 45, "which" should read while Signed and sealed this 30th day of December 1969.

n: Commissmner of Patents WILLIAM E. SCHUYLER, 

